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Morelli L, Cartaxana P, Cruz S. Food shaped photosynthesis: Photophysiology of the sea slug Elysia viridis fed with two alternative chloroplast donors. OPEN RESEARCH EUROPE 2024; 3:107. [PMID: 38725452 PMCID: PMC11079582 DOI: 10.12688/openreseurope.16162.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 02/26/2024] [Indexed: 05/12/2024]
Abstract
Background Some Sacoglossa sea slugs steal and integrate chloroplasts derived from the algae they feed on into their cells where they continue to function photosynthetically, a process termed kleptoplasty. The stolen chloroplasts - kleptoplasts - can maintain their functionality up to several months and support animal metabolism. However, chloroplast longevity can vary depending on sea slug species and algal donor. In this study, we focused on Elysia viridis, a polyphagous species that is mostly found associated with the macroalga Codium tomentosum, but that was reported to eat other macroalgae, including Chaetomorpha sp. Methods We have investigated the changes in E. viridis physiology when provided with the two different food sources to evaluate to which extent the photosynthetic and photoprotective mechanisms of the algae chloroplasts matched those of the plastids once in the animal cells. To perform the study, we rely on the evaluation of chlorophyll a variable fluorescence to study the photophysiological state of the integrated kleptoplasts and high-performance liquid chromatography (HPLC) to study variations in the photosynthetic pigments. Results We observed that the photosynthetic efficiency of E. viridis is lower when fed with Chaetomorpha. Also, significant differences were observed in the non-photochemical quenching (NPQ) abilities of the sea slugs. While sea slugs fed with C. tomentosum react similarly to high-light stress as the alga, E. viridis hosting Chaetomorpha chloroplasts were unable to properly recover from photoinhibition or perform a functional xanthophyll cycle (XC). Conclusions Our results showed that, even if the sea slugs fed with the two algae show photosynthetic activities like the respective algal donors, not all the photoprotective mechanisms present in Chaetomorpha can be maintained in E. viridis. This indicates that the functionality of the kleptoplasts does not depend solely on their origin but also on the degree of compatibility with the animal species integrating them.
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Affiliation(s)
- Luca Morelli
- CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Aveiro District, 3810-193, Portugal
| | - Paulo Cartaxana
- CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Aveiro District, 3810-193, Portugal
| | - Sónia Cruz
- CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Aveiro District, 3810-193, Portugal
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Morelli L, Havurinne V, Madeira D, Martins P, Cartaxana P, Cruz S. Photoprotective mechanisms in Elysia species hosting Acetabularia chloroplasts shed light on host-donor compatibility in photosynthetic sea slugs. PHYSIOLOGIA PLANTARUM 2024; 176:e14273. [PMID: 38566156 DOI: 10.1111/ppl.14273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/13/2024] [Accepted: 03/18/2024] [Indexed: 04/04/2024]
Abstract
Sacoglossa sea slugs have garnered attention due to their ability to retain intracellular functional chloroplasts from algae, while degrading other algal cell components. While protective mechanisms that limit oxidative damage under excessive light are well documented in plants and algae, the photoprotective strategies employed by these photosynthetic sea slugs remain unresolved. Species within the genus Elysia are known to retain chloroplasts from various algal sources, but the extent to which the metabolic processes from the donor algae can be sustained by the sea slugs is unclear. By comparing responses to high-light conditions through kinetic analyses, molecular techniques, and biochemical assays, this study shows significant differences between two photosynthetic Elysia species with chloroplasts derived from the green alga Acetabularia acetabulum. Notably, Elysia timida displayed remarkable tolerance to high-light stress and sophisticated photoprotective mechanisms such as an active xanthophyll cycle, efficient D1 protein recycling, accumulation of heat-shock proteins and α-tocopherol. In contrast, Elysia crispata exhibited absence or limitations in these photoprotective strategies. Our findings emphasize the intricate relationship between the host animal and the stolen chloroplasts, highlighting different capacities to protect the photosynthetic organelle from oxidative damage.
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Affiliation(s)
- Luca Morelli
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Vesa Havurinne
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Diana Madeira
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Patrícia Martins
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Paulo Cartaxana
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
| | - Sónia Cruz
- ECOMARE-Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro, Portugal
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Cartaxana P, Morelli L, Cassin E, Havurinne V, Cabral M, Cruz S. Prey species and abundance affect growth and photosynthetic performance of the polyphagous sea slug Elysia crispata. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230810. [PMID: 37650060 PMCID: PMC10465201 DOI: 10.1098/rsos.230810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 08/10/2023] [Indexed: 09/01/2023]
Abstract
Some sacoglossan sea slugs steal functional macroalgal chloroplasts (kleptoplasts). In this study, we investigated the effects of algal prey species and abundance on the growth and photosynthetic capacity of the tropical polyphagous sea slug Elysia crispata. Recently hatched sea slugs fed and acquired chloroplasts from the macroalga Bryopsis plumosa, but not from Acetabularia acetabulum. However, adult sea slugs were able to switch diet to A. acetabulum, rapidly replacing the great majority of the original kleptoplasts. When fed with B. plumosa, higher feeding frequency resulted in significantly higher growth and kleptoplast photosynthetic yield, as well as a slower relative decrease in these parameters upon starvation. Longevity of A. acetabulum-derived chloroplasts in E. crispata was over twofold that of B. plumosa. Furthermore, significantly lower relative weight loss under starvation was observed in sea slugs previously fed on A. acetabulum than on B. plumosa. This study shows that functionality and longevity of kleptoplasts in photosynthetic sea slugs depend on the origin of the plastids. Furthermore, we have identified A. acetabulum as a donor of photosynthetically efficient chloroplasts common to highly specialized monophagous and polyphagous sea slugs capable of long-term retention, which opens new experimental routes to unravel the unsolved mysteries of kleptoplasty.
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Affiliation(s)
- Paulo Cartaxana
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Luca Morelli
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Elena Cassin
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Vesa Havurinne
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Miguel Cabral
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
| | - Sónia Cruz
- ECOMARE – Laboratory for Innovation and Sustainability of Marine Biological Resources, CESAM – Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Aveiro 3810-193, Portugal
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Rieseberg TP, Dadras A, Fürst-Jansen JMR, Dhabalia Ashok A, Darienko T, de Vries S, Irisarri I, de Vries J. Crossroads in the evolution of plant specialized metabolism. Semin Cell Dev Biol 2023; 134:37-58. [PMID: 35292191 DOI: 10.1016/j.semcdb.2022.03.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 02/17/2022] [Accepted: 03/04/2022] [Indexed: 12/25/2022]
Abstract
The monophyletic group of embryophytes (land plants) stands out among photosynthetic eukaryotes: they are the sole constituents of the macroscopic flora on land. In their entirety, embryophytes account for the majority of the biomass on land and constitute an astounding biodiversity. What allowed for the massive radiation of this particular lineage? One of the defining features of all land plants is the production of an array of specialized metabolites. The compounds that the specialized metabolic pathways of embryophytes produce have diverse functions, ranging from superabundant structural polymers and compounds that ward off abiotic and biotic challenges, to signaling molecules whose abundance is measured at the nanomolar scale. These specialized metabolites govern the growth, development, and physiology of land plants-including their response to the environment. Hence, specialized metabolites define the biology of land plants as we know it. And they were likely a foundation for their success. It is thus intriguing to find that the closest algal relatives of land plants, freshwater organisms from the grade of streptophyte algae, possess homologs for key enzymes of specialized metabolic pathways known from land plants. Indeed, some studies suggest that signature metabolites emerging from these pathways can be found in streptophyte algae. Here we synthesize the current understanding of which routes of the specialized metabolism of embryophytes can be traced to a time before plants had conquered land.
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Affiliation(s)
- Tim P Rieseberg
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Armin Dadras
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Janine M R Fürst-Jansen
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Amra Dhabalia Ashok
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Tatyana Darienko
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Sophie de Vries
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany
| | - Iker Irisarri
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany; University of Goettingen, Campus Institute Data Science (CIDAS), Goldschmidstr. 1, 37077 Goettingen, Germany
| | - Jan de Vries
- University of Goettingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Goldschmidtstr. 1, 37077 Goettingen, Germany; University of Goettingen, Campus Institute Data Science (CIDAS), Goldschmidstr. 1, 37077 Goettingen, Germany; University of Goettingen, Goettingen Center for Molecular Biosciences (GZMB), Department of Applied Bioinformatics, Goldschmidtsr. 1, 37077 Goettingen, Germany.
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Seki S, Nakaniwa T, Castro-Hartmann P, Sader K, Kawamoto A, Tanaka H, Qian P, Kurisu G, Fujii R. Structural insights into blue-green light utilization by marine green algal light harvesting complex II at 2.78 Å. BBA ADVANCES 2022; 2:100064. [PMID: 37082593 PMCID: PMC10074980 DOI: 10.1016/j.bbadva.2022.100064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Light-harvesting complex II (LHCII) present in plants and green algae absorbs solar energy to promote photochemical reactions. A marine green macroalga, Codium fragile, exhibits the unique characteristic of absorbing blue-green light from the sun during photochemical reactions while being underwater owing to the presence of pigment-altered LHCII called siphonaxanthin-chlorophyll a/b-binding protein (SCP). In this study, we determined the structure of SCP at a resolution of 2.78 Å using cryogenic electron microscopy. SCP has a trimeric structure, wherein each monomer containing two lutein and two chlorophyll a molecules in the plant-type LHCII are replaced by siphonaxanthin and its ester and two chlorophyll b molecules, respectively. Siphonaxanthin occupies the binding site in SCP having a polarity in the trimeric inner core, and exhibits a distorted conjugated chain comprising a carbonyl group hydrogen bonded to a cysteine residue of apoprotein. These features suggest that the siphonaxanthin molecule is responsible for the characteristic green absorption of SCP. The replaced chlorophyll b molecules extend the region of the stromal side chlorophyll b cluster, spanning two adjacent monomers.
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Affiliation(s)
- Soichiro Seki
- Division of Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558–8585, Japan
| | - Tetsuko Nakaniwa
- Institute for Protein Research, Osaka University, Suita, Osaka 565–0871, Japan
| | - Pablo Castro-Hartmann
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Kasim Sader
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Akihiro Kawamoto
- Institute for Protein Research, Osaka University, Suita, Osaka 565–0871, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565–9871, Japan
| | - Hideaki Tanaka
- Institute for Protein Research, Osaka University, Suita, Osaka 565–0871, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565–9871, Japan
| | - Pu Qian
- Materials and Structural Analysis, Thermo Fisher Scientific, Achtseweg Noord 5, 5651 GG Eindhoven, Netherlands
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka 565–0871, Japan
- Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita, Osaka 565–9871, Japan
| | - Ritsuko Fujii
- Division of Molecular Materials Science, Graduate School of Science, Osaka City University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558–8585, Japan
- Department of Chemistry, Graduate School of Science, Osaka Metropolitan University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558–8585, Japan
- Research Center for Artificial Photosynthesis (ReCAP), Osaka Metropolitan University, 3-3-138, Sugimoto, Sumiyoshi-ku, Osaka 558–8585, Japan
- Corresponding author.
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Serôdio J, Moreira D, Bastos A, Cardoso V, Frommlet J, Frankenbach S. Hysteresis light curves: a protocol for characterizing the time dependence of the light response of photosynthesis. PHOTOSYNTHESIS RESEARCH 2022; 154:57-74. [PMID: 36057004 DOI: 10.1007/s11120-022-00954-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 08/19/2022] [Indexed: 06/15/2023]
Abstract
Photosynthesis vs. light curves (LCs) have played a central role in photosynthesis research for decades. They are the commonest form of describing how photosynthesis responds to changes in light, being frequently used for characterizing photoacclimation. However, LCs are often interpreted exclusively regarding the response to light intensity, the effects of time of exposure not being explicitly considered. This study proposes the use of 'hysteresis light curves' (HLC), an experimental protocol focused on the cumulative effects of light exposure to obtain information on the time dependence of photosynthetic light responses. HLC are generated by exposing samples to a symmetrical sequence of increasing and decreasing light levels. The comparison of the light-increasing and the light-decreasing phases allows the quantification of the hysteresis caused by high-light exposure, the magnitude and direction of which inform on the activation, and subsequent relaxation of high-light-induced photosynthetic processes. HLCs of the chlorophyll fluorescence indices rETR (relative electron transport rate of photosystem II) and Y(NPQ) (index of non-photochemical quenching) were measured on cyanobacteria, algae, and plants, with the aim of identifying main patterns of hysteresis and their diversity. A non-parametric index is proposed to quantify the magnitude and direction of hysteresis in HLCs of rETR and Y(NPQ). The results of this study show that HLCs can provide additional relevant information on the time dependence of the light response of photosynthetic samples, not obtainable from conventional LCs, useful for phenotyping photosynthetic traits, including photoacclimation state and kinetics of light activation and relaxation of electron flow and energy dissipation processes.
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Affiliation(s)
- João Serôdio
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
| | - Daniel Moreira
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Alexandra Bastos
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Vera Cardoso
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Jörg Frommlet
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
| | - Silja Frankenbach
- Department of Biology and CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal
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Fürst-Jansen JM, de Vries S, Lorenz M, von Schwartzenberg K, Archibald JM, de Vries J. Submergence of the filamentous Zygnematophyceae Mougeotia induces differential gene expression patterns associated with core metabolism and photosynthesis. PROTOPLASMA 2022; 259:1157-1174. [PMID: 34939169 PMCID: PMC9385824 DOI: 10.1007/s00709-021-01730-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/06/2021] [Indexed: 06/01/2023]
Abstract
The streptophyte algal class Zygnematophyceae is the closest algal sister lineage to land plants. In nature, Zygnematophyceae can grow in both terrestrial and freshwater habitats and how they do this is an important unanswered question. Here, we studied what happens to the zygnematophyceaen alga Mougeotia sp., which usually occurs in permanent and temporary freshwater bodies, when it is shifted to liquid growth conditions after growth on a solid substrate. Using global differential gene expression profiling, we identified changes in the core metabolism of the organism interlinked with photosynthesis; the latter went hand in hand with measurable impact on the photophysiology as assessed via pulse amplitude modulation (PAM) fluorometry. Our data reveal a pronounced change in the overall physiology of the alga after submergence and pinpoint candidate genes that play a role. These results provide insight into the importance of photophysiological readjustment when filamentous Zygnematophyceae transition between terrestrial and aquatic habitats.
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Affiliation(s)
- Janine M.R. Fürst-Jansen
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goldschmidtstr. 1, University of Goettingen, 37077 Goettingen, Germany
| | - Sophie de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goldschmidtstr. 1, University of Goettingen, 37077 Goettingen, Germany
| | - Maike Lorenz
- Department of Experimental Phycology and SAG Culture Collection of Algae, Albrecht-von-Haller Institute for Plant Science, University of Goettingen, Nikolausberger Weg 18, 37073 Goettingen, Germany
| | - Klaus von Schwartzenberg
- Institute of Plant Science and Microbiology, Microalgae and Zygnematophyceae Collection Hamburg (MZCH) and Aquatic Ecophysiology and Phycology, Universität Hamburg, Ohnhorststr. 18, 22609 Hamburg, Germany
| | - John M. Archibald
- Department of Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, NS B3H 4R2 Canada
| | - Jan de Vries
- Department of Applied Bioinformatics, Institute for Microbiology and Genetics, University of Goettingen, Goldschmidtstr. 1, University of Goettingen, 37077 Goettingen, Germany
- Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany
- Campus Institute Data Science (CIDAS), University of Goettingen, Goldschmidstr. 1, 37077 Goettingen, Germany
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Cikoš AM, Šubarić D, Roje M, Babić J, Jerković I, Jokić S. Recent advances on macroalgal pigments and their biological activities (2016–2021). ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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Seki S, Yamano Y, Oka N, Kamei Y, Fujii R. Discovery of a novel siphonaxanthin biosynthetic precursor in Codium fragile that accumulates only by exposure to blue-green light. FEBS Lett 2022; 596:1544-1555. [PMID: 35460262 DOI: 10.1002/1873-3468.14357] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 04/04/2022] [Indexed: 02/02/2023]
Abstract
Photosynthetic organisms adapt to a variety of light conditions. Codium fragile, a macrosiphonous green alga, binds a unique carbonyl carotenoid, siphonaxanthin, to its major photosynthetic light-harvesting complexes, allowing it to utilize dim blue-green light for photosynthesis. Here, we describe the absolute chemical structure of a novel siphonaxanthin biosynthetic precursor, 19-deoxysiphonaxanthin, that accumulates specifically in the photosynthetic antenna only when cultivated under blue-green light. The action spectra of pigment accumulation suggest that siphonaxanthin biosynthesis is regulated by a specific wavelength profile. The results provide clues to a new acclimation mechanism to withstand hours of intense light at low tide and why siphonous algae have been growing invasively on the world's coasts for more than a century.
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Affiliation(s)
- Soichiro Seki
- Division of Molecular Materials Science, Graduate School of Science, Osaka City University, Japan
| | - Yumiko Yamano
- Comprehensive Education and Research Center, Kobe Pharmaceutical University, Japan
| | - Naohiro Oka
- Bio-innovation Research Center (Naruto Campus), Tokushima University, Naruto, Japan
| | - Yasuhiro Kamei
- Spectrography and Bioimaging Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Ritsuko Fujii
- Division of Molecular Materials Science, Graduate School of Science, Osaka City University, Japan.,Research Center for Artificial Photosynthesis (ReCAP), Osaka Metropolitan University, Japan
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van den Berg TE, Croce R. The Loroxanthin Cycle: A New Type of Xanthophyll Cycle in Green Algae (Chlorophyta). FRONTIERS IN PLANT SCIENCE 2022; 13:797294. [PMID: 35251077 PMCID: PMC8891138 DOI: 10.3389/fpls.2022.797294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/18/2022] [Indexed: 06/14/2023]
Abstract
Xanthophyll cycles (XC) have proven to be major contributors to photoacclimation for many organisms. This work describes a light-driven XC operating in the chlorophyte Chlamydomonas reinhardtii and involving the xanthophylls Lutein (L) and Loroxanthin (Lo). Pigments were quantified during a switch from high to low light (LL) and at different time points from cells grown in Day/Night cycle. Trimeric LHCII was purified from cells acclimated to high or LL and their pigment content and spectroscopic properties were characterized. The Lo/(L + Lo) ratio in the cells varies by a factor of 10 between cells grown in low or high light (HL) leading to a change in the Lo/(L + Lo) ratio in trimeric LHCII from .5 in low light to .07 in HL. Trimeric LhcbMs binding Loroxanthin have 5 ± 1% higher excitation energy (EE) transfer (EET) from carotenoid to Chlorophyll as well as higher thermo- and photostability than trimeric LhcbMs that only bind Lutein. The Loroxanthin cycle operates on long time scales (hours to days) and likely evolved as a shade adaptation. It has many similarities with the Lutein-epoxide - Lutein cycle (LLx) of plants.
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Zhao W, Yang XQ, Zhang QS, Tan Y, Liu Z, Ma MY, Wang MX, Xu B. Photoinactivation of the oxygen-evolving complex regulates the photosynthetic strategy of the seagrass Zostera marina. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2021; 222:112259. [PMID: 34274827 DOI: 10.1016/j.jphotobiol.2021.112259] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/09/2021] [Accepted: 07/10/2021] [Indexed: 11/27/2022]
Abstract
Zostera marina, a widespread seagrass, evolved from a freshwater ancestor of terrestrial monocots and successfully transitioned into a completely submerged seagrass. We found that its oxygen-evolving complex (OEC) was partially inactivated in response to light exposure, as evidenced by both the increment of the relative variable fluorescence at the K-step and the downregulation of the OEC genes and proteins. This photosynthetic regulation was further addressed at both proteome and physiology levels by an in vivo study. The unchanged content of the ΔpH sensor PsbS protein and the non-photochemical quenching induction dynamics, described by a single exponential function, verified the absence of the fast qE component. Contents and activities of chlororespiration, Mehler reaction, malic acid synthesis, and photorespiration key enzymes were not upregulated, suggesting that alternative electron flows remained unactivated. Furthermore, neither significant production of singlet oxygen nor increment of total antioxidative capacity indicated that reactive oxygen species were not produced during light exposure. In summary, these low electron consumptions may allow Z. marina to efficiently use the limited electrons caused by partial OEC photoinactivation to maintain a normal carbon assimilation level.
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Affiliation(s)
- Wei Zhao
- Ocean School, Yantai University, Yantai 264005, PR China
| | - Xiao-Qi Yang
- Ocean School, Yantai University, Yantai 264005, PR China
| | | | - Ying Tan
- Ocean School, Yantai University, Yantai 264005, PR China
| | - Zhe Liu
- Ocean School, Yantai University, Yantai 264005, PR China
| | - Ming-Yu Ma
- Ocean School, Yantai University, Yantai 264005, PR China
| | - Meng-Xin Wang
- Ocean School, Yantai University, Yantai 264005, PR China
| | - Bin Xu
- Ocean School, Yantai University, Yantai 264005, PR China
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Zhao W, Zhang QS, Tan Y, Liu Z, Ma MY, Wang MX, Luo CY. An underlying mechanism of qE deficiency in marine angiosperm Zostera marina. PHOTOSYNTHESIS RESEARCH 2021; 148:87-99. [PMID: 33934290 DOI: 10.1007/s11120-021-00836-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 04/17/2021] [Indexed: 06/12/2023]
Abstract
Non-photochemical quenching (NPQ) of photosystem II (PSII) fluorescence is one of the most important protective mechanisms enabling the survival of phototropic organisms under high-light conditions. A low-efficiency NPQ, characterized by weak NPQ induction capacity and a low level of protective NPQ, was observed in the marine angiosperm Zostera marina, which inhabits the shallow water regions. Furthermore, chlorophyll fluorescence and Western blot analysis verified that the fast-inducted component of NPQ, i.e., the energy-dependent quenching (qE), was not present in this species. In contrast with the lack of PSII antenna quenching sites for qE induction in brown algae and the lack of functional XC in Ulvophyceae belonging to green algae, all the antenna proteins and the functional XC are present in Z. marina. A novel underlying mechanism was observed that the limited construction of the trans-thylakoid proton gradient (ΔpH) caused by photoinactivation of the oxygen evolving complex (OEC) did not induce protonation of PsbS, thus explaining the inability to form quenching sites for qE induction. Although the ΔpH established under light exposure activated violaxanthin (V) de-epoxidase enzyme to catalyze conversion of V via antheraxanthin (A) and then to zeaxanthin (Z), the quenching capacity of de-epoxidized pigment was weak in Z. marina. We suggest that the low-efficiency NPQ was conducive to efficiently utilize the limited electrons to perform photosynthesis, resisting the adverse effect of OEC photoinactivation on the photosynthetic rate.
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Affiliation(s)
- Wei Zhao
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Quan Sheng Zhang
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China.
| | - Ying Tan
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Zhe Liu
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Ming Yu Ma
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Meng Xin Wang
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
| | - Cheng Ying Luo
- Ocean School, Yantai University, Yantai, 264005, People's Republic of China
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13
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Iha C, Dougan KE, Varela JA, Avila V, Jackson CJ, Bogaert KA, Chen Y, Judd LM, Wick R, Holt KE, Pasella MM, Ricci F, Repetti SI, Medina M, Marcelino VR, Chan CX, Verbruggen H. Genomic adaptations to an endolithic lifestyle in the coral-associated alga Ostreobium. Curr Biol 2021; 31:1393-1402.e5. [PMID: 33548192 DOI: 10.1016/j.cub.2021.01.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/21/2020] [Accepted: 01/07/2021] [Indexed: 02/06/2023]
Abstract
The green alga Ostreobium is an important coral holobiont member, playing key roles in skeletal decalcification and providing photosynthate to bleached corals that have lost their dinoflagellate endosymbionts. Ostreobium lives in the coral's skeleton, a low-light environment with variable pH and O2 availability. We present the Ostreobium nuclear genome and a metatranscriptomic analysis of healthy and bleached corals to improve our understanding of Ostreobium's adaptations to its extreme environment and its roles as a coral holobiont member. The Ostreobium genome has 10,663 predicted protein-coding genes and shows adaptations for life in low and variable light conditions and other stressors in the endolithic environment. This alga presents a rich repertoire of light-harvesting complex proteins but lacks many genes for photoprotection and photoreceptors. It also has a large arsenal of genes for oxidative stress response. An expansion of extracellular peptidases suggests that Ostreobium may supplement its energy needs by feeding on the organic skeletal matrix, and a diverse set of fermentation pathways allows it to live in the anoxic skeleton at night. Ostreobium depends on other holobiont members for vitamin B12, and our metatranscriptomes identify potential bacterial sources. Metatranscriptomes showed Ostreobium becoming a dominant agent of photosynthesis in bleached corals and provided evidence for variable responses among coral samples and different Ostreobium genotypes. Our work provides a comprehensive understanding of the adaptations of Ostreobium to its extreme environment and an important genomic resource to improve our comprehension of coral holobiont resilience, bleaching, and recovery.
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Affiliation(s)
- Cintia Iha
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia.
| | - Katherine E Dougan
- School of Chemistry and Molecular Biosciences and Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Javier A Varela
- School of Microbiology, Centre for Synthetic Biology and Biotechnology, Environmental Research Institute, and APC Microbiome Institute, University College Cork, Cork T12 YN60, Ireland
| | - Viridiana Avila
- Pennsylvania State University, University Park, PA 16802, USA
| | | | - Kenny A Bogaert
- Phycology Research Group, Ghent University, Krijgslaan 281 S8, 9000 Gent, Belgium
| | - Yibi Chen
- School of Chemistry and Molecular Biosciences and Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Louise M Judd
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Ryan Wick
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
| | - Kathryn E Holt
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, VIC 3004, Australia; London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Marisa M Pasella
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Francesco Ricci
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Sonja I Repetti
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia
| | - Mónica Medina
- Pennsylvania State University, University Park, PA 16802, USA
| | - Vanessa R Marcelino
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia
| | - Cheong Xin Chan
- School of Chemistry and Molecular Biosciences and Australian Centre for Ecogenomics, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Heroen Verbruggen
- School of BioSciences, University of Melbourne, Melbourne, VIC 3010, Australia.
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14
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Melo Clavijo J, Frankenbach S, Fidalgo C, Serôdio J, Donath A, Preisfeld A, Christa G. Identification of scavenger receptors and thrombospondin-type-1 repeat proteins potentially relevant for plastid recognition in Sacoglossa. Ecol Evol 2020; 10:12348-12363. [PMID: 33209293 PMCID: PMC7663992 DOI: 10.1002/ece3.6865] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/20/2020] [Accepted: 08/27/2020] [Indexed: 12/24/2022] Open
Abstract
Functional kleptoplasty is a photosymbiotic relationship, in which photosynthetically active chloroplasts serve as an intracellular symbiont for a heterotrophic host. Among Metazoa, functional kleptoplasty is only found in marine sea slugs belonging to the Sacoglossa and recently described in Rhabdocoela worms. Although functional kleptoplasty has been intensively studied in Sacoglossa, the fundamentals of the specific recognition of the chloroplasts and their subsequent incorporation are unknown. The key to ensure the initiation of any symbiosis is the ability to specifically recognize the symbiont and to differentiate a symbiont from a pathogen. For instance, in photosymbiotic cnidarians, several studies have shown that the host innate immune system, in particular scavenger receptors (SRs) and thrombospondin-type-1 repeat (TSR) protein superfamily, is playing a major role in the process of recognizing and differentiating symbionts from pathogens. In the present study, SRs and TSRs of three Sacoglossa sea slugs, Elysia cornigera, Elysia timida, and Elysia chlorotica, were identified by translating available transcriptomes into potential proteins and searching for receptor specific protein and/or transmembrane domains. Both receptors classes are highly diverse in the slugs, and many new domain arrangements for each receptor class were found. The analyses of the gene expression of these three species provided a set of species-specific candidate genes, that is, SR-Bs, SR-Es, C-type lectins, and TSRs, that are potentially relevant for the recognition of kleptoplasts. The results set the base for future experimental studies to understand if and how these candidate receptors are indeed involved in chloroplast recognition.
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Affiliation(s)
- Jenny Melo Clavijo
- Fakultät für Mathematik und Naturwissenschaften, Zoologie und BiologiedidaktikBergische Universität WuppertalWuppertalGermany
| | - Silja Frankenbach
- Department of Biology and CESAM – Center for Environmental and Marine StudiesUniversity of AveiroAveiroPortugal
| | - Cátia Fidalgo
- Department of Biology and CESAM – Center for Environmental and Marine StudiesUniversity of AveiroAveiroPortugal
| | - João Serôdio
- Department of Biology and CESAM – Center for Environmental and Marine StudiesUniversity of AveiroAveiroPortugal
| | - Alexander Donath
- Center for Molecular Biodiversity ResearchZoological Research Museum Alexander KoenigBonnGermany
| | - Angelika Preisfeld
- Fakultät für Mathematik und Naturwissenschaften, Zoologie und BiologiedidaktikBergische Universität WuppertalWuppertalGermany
| | - Gregor Christa
- Fakultät für Mathematik und Naturwissenschaften, Zoologie und BiologiedidaktikBergische Universität WuppertalWuppertalGermany
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15
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Photoprotective Role of Neoxanthin in Plants and Algae. Molecules 2020; 25:molecules25204617. [PMID: 33050573 PMCID: PMC7587190 DOI: 10.3390/molecules25204617] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/08/2020] [Accepted: 10/09/2020] [Indexed: 11/17/2022] Open
Abstract
Light is a paramount parameter driving photosynthesis. However, excessive irradiance leads to the formation of reactive oxygen species that cause cell damage and hamper the growth of photosynthetic organisms. Xanthophylls are key pigments involved in the photoprotective response of plants and algae to excessive light. Of particular relevance is the operation of xanthophyll cycles (XC) leading to the formation of de-epoxidized molecules with energy dissipating capacities. Neoxanthin, found in plants and algae in two different isomeric forms, is involved in the light stress response at different levels. This xanthophyll is not directly involved in XCs and the molecular mechanisms behind its photoprotective activity are yet to be fully resolved. This review comprehensively addresses the photoprotective role of 9′-cis-neoxanthin, the most abundant neoxanthin isomer, and one of the major xanthophyll components in plants’ photosystems. The light-dependent accumulation of all-trans-neoxanthin in photosynthetic cells was identified exclusively in algae of the order Bryopsidales (Chlorophyta), that lack a functional XC. A putative photoprotective model involving all-trans-neoxanthin is discussed.
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16
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Fürst-Jansen JMR, de Vries S, de Vries J. Evo-physio: on stress responses and the earliest land plants. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3254-3269. [PMID: 31922568 PMCID: PMC7289718 DOI: 10.1093/jxb/eraa007] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 01/07/2020] [Indexed: 05/19/2023]
Abstract
Embryophytes (land plants) can be found in almost any habitat on the Earth's surface. All of this ecologically diverse embryophytic flora arose from algae through a singular evolutionary event. Traits that were, by their nature, indispensable for the singular conquest of land by plants were those that are key for overcoming terrestrial stressors. Not surprisingly, the biology of land plant cells is shaped by a core signaling network that connects environmental cues, such as stressors, to the appropriate responses-which, thus, modulate growth and physiology. When did this network emerge? Was it already present when plant terrestrialization was in its infancy? A comparative approach between land plants and their algal relatives, the streptophyte algae, allows us to tackle such questions and resolve parts of the biology of the earliest land plants. Exploring the biology of the earliest land plants might shed light on exactly how they overcame the challenges of terrestrialization. Here, we outline the approaches and rationale underlying comparative analyses towards inferring the genetic toolkit for the stress response that aided the earliest land plants in their conquest of land.
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Affiliation(s)
- Janine M R Fürst-Jansen
- University of Göttingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Göttingen, Germany
| | - Sophie de Vries
- Population Genetics, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Jan de Vries
- University of Göttingen, Institute for Microbiology and Genetics, Department of Applied Bioinformatics, Göttingen, Germany
- University of Göttingen, Göttingen Center for Molecular Biosciences (GZMB), Göttingen, Germany
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17
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Sun KM, Gao C, Zhang J, Tang X, Wang Z, Zhang X, Li Y. Rapid formation of antheraxanthin and zeaxanthin in seconds in microalgae and its relation to non-photochemical quenching. PHOTOSYNTHESIS RESEARCH 2020; 144:317-326. [PMID: 32323065 DOI: 10.1007/s11120-020-00739-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 03/22/2020] [Indexed: 06/11/2023]
Abstract
The violaxanthin (V)-antheraxanthin (A)-zeaxanthin (Z) (VAZ) cycle was deemed a non-second-scale process of photoprotection in higher plants and microalgae, but the validity of this view has not been confirmed. To test this view, we explored responses of the VAZ cycle and the relationship between the VAZ cycle and non-photochemical quenching (NPQ) under highlight at second and minute scales in Heterosigma akashiwo and Platymonas sp. Both A and Z were generated in H. akashiwo during 15 s of light exposure, whereas only A rapidly accumulated within 15 s of exposure in Platymonas sp. The above results, together with a time-dependent sigmoidal relationship between the VAZ cycle (de-epoxidation state, A/Chl a, and Z/Chl a) and NPQ, proved that the VAZ cycle was a second-scale process related to NPQ. In addition, we found that not all NPQ was dependent on the VAZ cycle and suggested that NPQ model should be carefully modified due to the species-specific proportions of de-epoxidation-dependent NPQ.
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Affiliation(s)
- Kai-Ming Sun
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China
- Laboratory of Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology (Qingdao), 1 Wenhai Road, Aoshanwei, Jimo, Qingdao, 266237, Shandong, People's Republic of China
- College of Marine Life, Ocean University of China, 5 Rushan Road, Qingdao, 266003, Shandong, People's Republic of China
| | - Chunlei Gao
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China
| | - Jing Zhang
- Department of Biological and Chemical Engineering, Qingdao Technical College, 369 Qiantangjiang Road, Qingdao, 266555, Shandong, People's Republic of China
| | - Xuexi Tang
- College of Marine Life, Ocean University of China, 5 Rushan Road, Qingdao, 266003, Shandong, People's Republic of China
| | - Zongling Wang
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China
| | - Xuelei Zhang
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China
| | - Yan Li
- SOA Key Laboratory of Science and Engineering for Marine Ecology and Environment, First Institute of Oceanography, Ministry of Natural Resources, 6 Xianxialing Road, Qingdao, 266061, Shandong, People's Republic of China.
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18
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Donohoo SA, Wade RM, Sherwood AR. Finding the Sweet Spot: Sub-Ambient Light Increases Fitness and Kleptoplast Survival in the Sea Slug Plakobranchus cf. ianthobaptus Gould, 1852. THE BIOLOGICAL BULLETIN 2020; 238:154-166. [PMID: 32597715 DOI: 10.1086/709371] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sacoglossans, or "sap-sucking" sea slugs, are primarily algivorous, with many taxa exhibiting kleptoplasty, the feeding and retaining of photosynthetically active chloroplasts from algae. The Plakobranchus species complex exhibits some of the longest kleptoplast retention and survival times under starvation conditions, but the contributions of these kleptoplasts to their survival and overall fitness have been widely debated. In this study we assessed the effects of starvation and light on the fitness of Plakobranchus cf. ianthobaptus and its kleptoplasts by placing starved individuals in eight daily average light treatments, ranging from near dark (2 µmol photon m-2 s-1) to ambient light (470 µmol photon m-2 s-1). Slug weight was used as a metric of fitness, and kleptoplast photosynthetic activity was determined via maximum quantum yield (Fv/Fm) by pulse-amplitude modulated fluorometry as a proxy for kleptoplast health. Plakobranchus individuals in near-dark and high light treatments (>160 µmol photon m-2 s-1) experienced significantly greater weight loss than those in low light (65 µmol photon m-2 s-1) and moderate light treatments (95-135 µmol photon m-2 s-1). Additionally, individuals in high light treatments experienced a rapid decline in kleptoplast photosynthetic activity, while all other treatments experienced minimal decline. This relationship between kleptoplast degradation and weight loss suggests an important link between fitness and kleptoplasty. Given the significant negative effects of ambient conditions, regular refreshment and replenishment of kleptoplasts or physiological or behavioral adjustments are likely employed for the benefits of kleptoplasty to be maintained.
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19
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Lacour T, Babin M, Lavaud J. Diversity in Xanthophyll Cycle Pigments Content and Related Nonphotochemical Quenching (NPQ) Among Microalgae: Implications for Growth Strategy and Ecology. JOURNAL OF PHYCOLOGY 2020; 56:245-263. [PMID: 31674660 DOI: 10.1111/jpy.12944] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 10/04/2019] [Indexed: 05/12/2023]
Abstract
Xanthophyll cycle-related nonphotochemical quenching (NPQ), which is present in most photoautotrophs, allows dissipation of excess light energy. Xanthophyll cycle-related NPQ depends principally on xanthophyll cycle pigments composition and their effective involvement in NPQ. Xanthophyll cycle-related NPQ is tightly controlled by environmental conditions in a species-/strain-specific manner. These features are especially relevant in microalgae living in a complex and highly variable environment. The goal of this study was to perform a comparative assessment of NPQ ecophysiologies across microalgal taxa in order to underline the specific involvement of NPQ in growth adaptations and strategies. We used both published results and data acquired in our laboratory to understand the relationships between growth conditions (irradiance, temperature, and nutrient availability), xanthophyll cycle composition, and xanthophyll cycle pigments quenching efficiency in microalgae from various taxa. We found that in diadinoxanthin-containing species, the xanthophyll cycle pigment pool is controlled by energy pressure in all species. At any given energy pressure, however, the diatoxanthin content is higher in diatoms than in other diadinoxanthin-containing species. XC pigments quenching efficiency is species-specific and decreases with acclimation to higher irradiances. We found a clear link between the natural light environment of species/ecotypes and quenching efficiency amplitude. The presence of diatoxanthin or zeaxanthin at steady state in all species examined at moderate and high irradiances suggests that cells maintain a light-harvesting capacity in excess to cope with potential decrease in light intensity.
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Affiliation(s)
| | - Marcel Babin
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Johann Lavaud
- Takuvik Joint International Laboratory UMI3376, CNRS (France) & ULaval (Canada), Département de Biologie, Université Laval, Pavillon Alexandre-Vachon, 1045, Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
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20
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Domesticated Populations of Codium tomentosum Display Lipid Extracts with Lower Seasonal Shifts than Conspecifics from the Wild-Relevance for Biotechnological Applications of this Green Seaweed. Mar Drugs 2020; 18:md18040188. [PMID: 32244516 PMCID: PMC7230330 DOI: 10.3390/md18040188] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/06/2023] Open
Abstract
In the last decades, the use of algae in biotechnology and food industries has experienced an exponential growth. Codium tomentosum is a green macroalgae with high biotechnological potential, due to its rich lipidome, although few studies have addressed it. This study aimed to investigate the seasonal changes in lipid and pigment profiles of C. tomentosum, as well as to screen its antioxidant activity, in order to evaluate its natural plasticity. Samples of C. tomentosum were collected in two different seasons, early-autumn (September/October) and spring (May), in the Portuguese coast (wild samples), and in a land-based integrated multitrophic aquaculture (IMTA) system (IMTA samples). Total lipid extracts were analysed by LC-MS, GC-MS, and HPLC, and antioxidant activity was screened through free radical scavenging potential against DPPH and 2,20-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals. Wild samples showed a high seasonal variability, modifying their lipidome and pigment profiles according to environmental shifts, while IMTA samples showed a relatively stable composition due to early-stage culturing in controlled conditions. The lipids that contributed the most to seasonal discrimination were glycolipids (monogalactosyl diacylglycerol - MGDG and digalactosyl diacylglycerol - DGDG) and the lyso forms of phospholipids and glycolipids. Lipid extracts showed antioxidant activity ranging from 61 ± 2 to 115 ± 35 µmol Trolox g-1 of lipid extract in DPPH assay and from 532 ± 73 to 927 ± 92 µmol Trolox g-1 of lipid extract in ABTS assay, with a more intense antioxidant activity in wild spring samples. This study revealed that wild specimens of C. tomentosum presented a higher plasticity to cope with seasonal environmental changes, adjusting their lipid, pigment, and bioactivity profiles, while IMTA samples, cultured under controlled conditions, displayed more stable lipidome and pigment compositions.
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21
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Akhtar P, Nowakowski PJ, Wang W, Do TN, Zhao S, Siligardi G, Garab G, Shen JR, Tan HS, Lambrev PH. Spectral tuning of light-harvesting complex II in the siphonous alga Bryopsis corticulans and its effect on energy transfer dynamics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148191. [PMID: 32201306 DOI: 10.1016/j.bbabio.2020.148191] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 03/11/2020] [Accepted: 03/13/2020] [Indexed: 12/17/2022]
Abstract
Light-harvesting complex II (LHCII) from the marine green macroalga Bryopsis corticulans is spectroscopically characterized to understand the structural and functional changes resulting from adaptation to intertidal environment. LHCII is homologous to its counterpart in land plants but has a different carotenoid and chlorophyll (Chl) composition. This is reflected in the steady-state absorption, fluorescence, linear dichroism, circular dichroism and anisotropic circular dichroism spectra. Time-resolved fluorescence and two-dimensional electronic spectroscopy were used to investigate the consequences of this adaptive change in the pigment composition on the excited-state dynamics. The complex contains additional Chl b spectral forms - absorbing at around 650 nm and 658 nm - and lacks the red-most Chl a forms compared with higher-plant LHCII. Similar to plant LHCII, energy transfer between Chls occurs on timescales from under hundred fs (mainly from Chl b to Chl a) to several picoseconds (mainly between Chl a pools). However, the presence of long-lived, weakly coupled Chl b and Chl a states leads to slower exciton equilibration in LHCII from B. corticulans. The finding demonstrates a trade-off between the enhanced absorption of blue-green light and the excitation migration time. However, the adaptive change does not result in a significant drop in the overall photochemical efficiency of Photosystem II. These results show that LHCII is a robust adaptable system whose spectral properties can be tuned to the environment for optimal light harvesting.
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Affiliation(s)
- Parveen Akhtar
- Biological Research Centre, Szeged, Hungary; ELI-ALPS, ELI Nonprofit Ltd., Szeged, Hungary
| | - Paweł J Nowakowski
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore
| | - Wenda Wang
- Photosynthesis Research Centre, Chinese Academy of Sciences, Beijing, China
| | - Thanh Nhut Do
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore
| | - Songhao Zhao
- Photosynthesis Research Centre, Chinese Academy of Sciences, Beijing, China
| | - Giuliano Siligardi
- Diamond Light Source Ltd., Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Győző Garab
- Biological Research Centre, Szeged, Hungary; Department of Physics, Faculty of Science, University of Ostrava, Czech Republic
| | - Jian-Ren Shen
- Photosynthesis Research Centre, Chinese Academy of Sciences, Beijing, China; Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan
| | - Howe-Siang Tan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore.
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22
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Isolation and Characterization of Two Microalgal Isolates from Vietnam with Potential for Food, Feed, and Biodiesel Production. ENERGIES 2020. [DOI: 10.3390/en13040898] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Microalgae are promising feedstock for the production of biodiesel and diverse medium- and high-value products such as pigments and polyunsaturated fatty acids. The importance of strain selection adapted to specific environments is important for economical purposes. We characterize here two microalgal strains, isolated from wastewater of shrimp cultivation ponds in Vietnam. Based on the 18S rDNA-ITS region, one strain belongs to the Eustigmatophyceae class and is identical to the Nannochloropsis salina isolate D12 (JX185299.1), while the other is a Chlorophyceae belonging to the Desmodesmus genus, which possesses a S516 group I intron in its 18S rDNA gene. The N. salina strain is a marine and oleaginous microalga (40% of dry weight (DW) at stationary phase) whole oil is rich in saturated fatty acids (around 45% of C16:0) suitable for biodiesel and contains a few percent of eicosapentaenoic acid (C20:5). The Desmodesmus isolate can assimilate acetate and ammonium and is rich in lutein. Its oil contains around 40%–50% α-linolenic acid (C18:3), an essential fatty acid. Since they tolerate various salinities (10% to 35‰), both strains are thus interesting for biodiesel or aquaculture valorization in coastal and tropical climate where water, nutrient, and salinity availability vary greatly depending on the season.
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Pierangelini M, Glaser K, Mikhailyuk T, Karsten U, Holzinger A. Light and Dehydration but Not Temperature Drive Photosynthetic Adaptations of Basal Streptophytes (Hormidiella, Streptosarcina and Streptofilum) Living in Terrestrial Habitats. MICROBIAL ECOLOGY 2019; 77:380-393. [PMID: 29974184 PMCID: PMC6394494 DOI: 10.1007/s00248-018-1225-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 06/24/2018] [Indexed: 05/05/2023]
Abstract
Streptophyte algae are the ancestors of land plants, and several classes contain taxa that are adapted to an aero-terrestrial lifestyle. In this study, four basal terrestrial streptophytes from the class Klebsormidiophyceae, including Hormidiella parvula; two species of the newly described genus Streptosarcina (S. costaricana and S. arenaria); and the newly described Streptofilum capillatum were investigated for their responses to radiation, desiccation and temperature stress conditions. All the strains showed low-light adaptation (Ik < 70 μmol photons m-2 s-1) but differed in photoprotective capacities (such as non-photochemical quenching). Acclimation to enhanced photon fluence rates (160 μmol photons m-2 s-1) increased photosynthetic performance in H. parvula and S. costaricana but not in S. arenaria, showing that low-light adaptation is a constitutive trait for S. arenaria. This lower-light adaptation of S. arenaria was coupled with a higher desiccation tolerance, providing further evidence that dehydration is a selective force shaping species occurrence in low light. For protection against ultraviolet radiation, all species synthesised and accumulated different amounts of mycosporine-like amino acids (MAAs). Biochemically, MAAs synthesised by Hormidiella and Streptosarcina were similar to MAAs from closely related Klebsormidium spp. but differed in retention time and spectral characteristics in S. capillatum. Unlike the different radiation and dehydration tolerances, Hormidiella, Streptosarcina and Streptofilum displayed preferences for similar thermal conditions. These species showed a temperature dependence of photosynthesis similar to respiration, contrasting with Klebsormidium spp. and highlighting an interspecific diversity in thermal requirements, which could regulate species distributions under temperature changes.
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Affiliation(s)
- Mattia Pierangelini
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria
- Laboratoire de Génétique et Physiologie des microalgues, InBioS/Phytosystems, Institut de Botanique, Université de Liège, Liege, 4000, Belgium
| | - Karin Glaser
- Applied Ecology and Phycology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Strasse 3, 18059, Rostock, Germany
| | - Tatiana Mikhailyuk
- M.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, Tereschenkivska Str. 2, Kyiv, 01004, Ukraine
| | - Ulf Karsten
- Applied Ecology and Phycology, Institute of Biological Sciences, University of Rostock, Albert-Einstein-Strasse 3, 18059, Rostock, Germany
| | - Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria.
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24
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Serôdio J, Schmidt W, Frommlet JC, Christa G, Nitschke MR. An LED-based multi-actinic illumination system for the high throughput study of photosynthetic light responses. PeerJ 2018; 6:e5589. [PMID: 30202661 PMCID: PMC6128260 DOI: 10.7717/peerj.5589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/15/2018] [Indexed: 11/20/2022] Open
Abstract
The responses of photosynthetic organisms to light stress are of interest for both fundamental and applied research. Functional traits related to the photoinhibition, the light-induced loss of photosynthetic efficiency, are particularly interesting as this process is a key limiting factor of photosynthetic productivity in algae and plants. The quantitative characterization of light responses is often time-consuming and calls for cost-effective high throughput approaches that enable the fast screening of multiple samples. Here we present a novel illumination system based on the concept of ‘multi-actinic imaging’ of in vivo chlorophyll fluorescence. The system is based on the combination of an array of individually addressable low power RGBW LEDs and custom-designed well plates, allowing for the independent illumination of 64 samples through the digital manipulation of both exposure duration and light intensity. The illumination system is inexpensive and easily fabricated, based on open source electronics, off-the-shelf components, and 3D-printed parts, and is optimized for imaging of chlorophyll fluorescence. The high-throughput potential of the system is illustrated by assessing the functional diversity in light responses of marine macroalgal species, through the fast and simultaneous determination of kinetic parameters characterizing the response to light stress of multiple samples. Although the presented illumination system was primarily designed for the measurement of phenotypic traits related to photosynthetic activity and photoinhibition, it can be potentially used for a number of alternative applications, including the measurement of chloroplast phototaxis and action spectra, or as the basis for microphotobioreactors.
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Affiliation(s)
- João Serôdio
- Department of Biology and CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - William Schmidt
- Department of Biology and CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - Jörg C Frommlet
- Department of Biology and CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - Gregor Christa
- Department of Biology and CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
| | - Matthew R Nitschke
- Department of Biology and CESAM-Centre for Environmental and Marine Studies, University of Aveiro, Aveiro, Portugal
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25
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Christa G, Pütz L, Sickinger C, Melo Clavijo J, Laetz EMJ, Greve C, Serôdio J. Photoprotective Non-photochemical Quenching Does Not Prevent Kleptoplasts From Net Photoinactivation. Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00121] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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26
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Giovagnetti V, Han G, Ware MA, Ungerer P, Qin X, Wang WD, Kuang T, Shen JR, Ruban AV. A siphonous morphology affects light-harvesting modulation in the intertidal green macroalga Bryopsis corticulans (Ulvophyceae). PLANTA 2018; 247:1293-1306. [PMID: 29460179 PMCID: PMC5945744 DOI: 10.1007/s00425-018-2854-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 01/20/2018] [Indexed: 05/18/2023]
Abstract
The macroalga Bryopsis corticulans relies on a sustained protective NPQ and a peculiar body architecture to efficiently adapt to the extreme light changes of intertidal shores. During low tides, intertidal algae experience prolonged high light stress. Efficient dissipation of excess light energy, measured as non-photochemical quenching (NPQ) of chlorophyll fluorescence, is therefore required to avoid photodamage. Light-harvesting regulation was studied in the intertidal macroalga Bryopsis corticulans, during high light and air exposure. Photosynthetic capacity and NPQ kinetics were assessed in different filament layers of the algal tufts and in intact chloroplasts to unravel the nature of NPQ in this siphonous green alga. We found that the morphology and pigment composition of the B. corticulans body provides functional segregation between surface sunlit filaments (protective state) and those that are underneath and undergo severe light attenuation (light-harvesting state). In the surface filaments, very high and sustained NPQ gradually formed. NPQ induction was triggered by the formation of transthylakoid proton gradient and independent of the xanthophyll cycle. PsbS and LHCSR proteins seem not to be active in the NPQ mechanism activated by this alga. Our results show that B. corticulans endures excess light energy pressure through a sustained protective NPQ, not related to photodamage, as revealed by the unusually quick restoration of photosystem II (PSII) function in the dark. This might suggest either the occurrence of transient PSII photoinactivation or a fast rate of PSII repair cycle.
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Affiliation(s)
- Vasco Giovagnetti
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Guangye Han
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Maxwell A Ware
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Petra Ungerer
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| | - Xiaochun Qin
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Wen-Da Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.
- Research Institute for Interdisciplinary Science, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima, Naka, Okayama, 700-8530, Japan.
| | - Alexander V Ruban
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
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Pierangelini M, Ryšánek D, Lang I, Adlassnig W, Holzinger A. Terrestrial adaptation of green algae Klebsormidium and Zygnema (Charophyta) involves diversity in photosynthetic traits but not in CO 2 acquisition. PLANTA 2017; 246:971-986. [PMID: 28721563 PMCID: PMC5633629 DOI: 10.1007/s00425-017-2741-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 07/09/2017] [Indexed: 05/20/2023]
Abstract
The basal streptophyte Klebsormidium and the advanced Zygnema show adaptation to terrestrialization. Differences are found in photoprotection and resistance to short-term light changes, but not in CO 2 acquisition. Streptophyte green algae colonized land about 450-500 million years ago giving origin to terrestrial plants. We aim to understand how their physiological adaptations are linked to the ecological conditions (light, water and CO2) characterizing modern terrestrial habitats. A new Klebsormidium isolate from a strongly acidic environment of a former copper mine (Schwarzwand, Austria) is investigated, in comparison to Klebsormidium cf. flaccidum and Zygnema sp. We show that these genera possess different photosynthetic traits and water requirements. Particularly, the Klebsormidium species displayed a higher photoprotection capacity, concluded from non-photochemical quenching (NPQ) and higher tolerance to high light intensity than Zygnema. However, Klebsormidium suffered from photoinhibition when the light intensity in the environment increased rapidly, indicating that NPQ is involved in photoprotection against strong and stable irradiance. Klebsormidium was also highly resistant to cellular water loss (dehydration) under low light. On the other hand, exposure to relatively high light intensity during dehydration caused a harmful over-reduction of the electron transport chain, leading to PSII damages and impairing the ability to recover after rehydration. Thus, we suggest that dehydration is a selective force shaping the adaptation of this species towards low light. Contrary to the photosynthetic characteristics, the inorganic carbon (C i ) acquisition was equivalent between Klebsormidium and Zygnema. Despite their different habitats and restriction to hydro-terrestrial environment, the three organisms showed similar use of CO2 and HCO3- as source of Ci for photosynthesis, pointing out a similar adaptation of their CO2-concentrating mechanisms to terrestrial life.
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Affiliation(s)
- Mattia Pierangelini
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria
| | - David Ryšánek
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, 12801, Prague 2, Czech Republic
- Laboratory of Environmental Microbiology, Institute of Microbiology of the CAS, v. v. i., Průmyslová 595, 252 42, Vestec, Czech Republic
| | - Ingeborg Lang
- Faculty of Life Sciences, Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Wolfram Adlassnig
- Faculty of Life Sciences, Core Facility Cell Imaging and Ultrastructure Research, University of Vienna, Althanstrasse 14, 1090, Vienna, Austria
| | - Andreas Holzinger
- Department of Botany, Functional Plant Biology, University of Innsbruck, 6020, Innsbruck, Austria.
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28
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Kleptoplast photosynthesis is nutritionally relevant in the sea slug Elysia viridis. Sci Rep 2017; 7:7714. [PMID: 28798379 PMCID: PMC5552801 DOI: 10.1038/s41598-017-08002-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 07/06/2017] [Indexed: 12/02/2022] Open
Abstract
Several sacoglossan sea slug species feed on macroalgae and incorporate chloroplasts into tubular cells of their digestive diverticula. We investigated the role of the “stolen” chloroplasts (kleptoplasts) in the nutrition of the sea slug Elysia viridis and assessed how their abundance, distribution and photosynthetic activity were affected by light and starvation. Elysia viridis individuals feeding on the macroalga Codium tomentosum were compared with starved specimens kept in dark and low light conditions. A combination of variable Chl a fluorescence and hyperspectral imaging, and HPLC pigment analysis was used to evaluate the spatial and temporal variability of photopigments and of the photosynthetic capacity of kleptoplasts. We show increased loss of weight and body length in dark-starved E. viridis as compared to low light-starved sea slugs. A more pronounced decrease in kleptoplast abundance and lower photosynthetic electron transport rates were observed in dark-starved sea slugs than in low light-starved animals. This study presents strong evidence of the importance of kleptoplast photosynthesis for the nutrition of E. viridis in periods of food scarcity. Deprived of photosynthates, E. viridis could accelerate the breakdown of kleptoplasts in the dark to satisfy its’ energy requirements.
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